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STRUCTURES (FORCES (Gravity, which pulls us towards the earth and gives…

STRUCTURES

FORCES

Gravity, which pulls us towards the earth and gives us weight.

The force of the wind.

Mechanical forces that move machines.

The fortce created by our own muscles.

Pressures of gases in closed containers.

Forces caused by the effects of heat, etc.

A structure is the set of elements in a body that are intended to resist the effects of the forces that act on it . It prevents a body from breaking or becoming too deformed

STRESSES

Livings things feel this effect — it can be very slight or if it is strong it can even hurt us. Obiects do not have feelings, but forces act on them in a similar way and produce deformations. In both cases this internal tension is called stress.

The tension varies depending on

The characteristics of the loads(intensity, direction, traiectory andpoint ofapplication)

The shape of the object bearing the loads.

TIPES

All bodies must have a structure that can resist forces.

Artificial

Are human made structures

Natural

Are not made by humans

The forces that act on a structure are called loads.

Fixed or permanent loads

Always affect the structure in the same way

Variable load

Are occasional and changeable

Shear or cutting

The forces act like two scissor blades they are very close together, moving in opposite directions, as they try to cut an object

Torsion

Forces try to twist a body. They try to turn the ends of the body in opposite directions

Forces try to flatten or compress a body. Opposing forces move inwards towards one another along the same trajectory and in opposite directions. The body tends to lose its shape and becomes compressed.

Forces try to bend a body. This stress acts on elements that are supported at their extremities and have a weight applied to them. There are two forces that are separated by a certain distance and a third force acting in the opposite direction.

Forces try to stretch the object they are acting upon. Opposing forces move outwards away fromthe body along the same trajectory but in opposite directions.

A force is anything that can deform a body (static effect) or change its state of movement or rest (dynamic effect)